240D windows

Well my first bet would be fuses, then the relay for the windows. The aluminum fuses corrode then they dont carry enough amps to do anything right at all. Then when a relay goes you never know what happens. Then check switches, take switches that work consistently and swap them too make sure. If not try cleaning all the ground wires for the system.

As I mentioned, the fuses seem ok. And since the wiring is cross/window (Left front and right rear), it clearly isn't the fuse. Hwere is the relay located? Since the window went down I think it's safe to assume there is current getting to the window but I could be wrong. More to the point, you suggest "check switches." That was the point of my question. How do you open the center console so you can get at the switches and check them? I feel about 90% certain that's the problem but I don't see any way that the center console comes off easily. For one thing, there's the (automatic) gear shift lever. Does the handle remove easily? It doesn't seem so. Sorry to not be so appreciative of your suggestion but it doesn't seem to address the problem I'm having.

Peter

Can't speak specifically to a 240D, but in the past I have to removed the ashtray, underneath there are a couple of screws to remove the ashtray frame and change cup, then the console wood will slide forward, and can be lifted up. The ring around the gear shift stays or can be lifted out (automatic, not sure about a manual transmission). Once the console wood is forward it can be lifted and the connections for the electric widows, mirror etc, can be unplugged from underneath.

The problem is usually dirt, grime and that occasional cup of coffee (with sugar) that gums up the switches. IMO a good reason to have a cup holder elsewhere.

In Mercedes in my past, I have had luck "cleaning" the switches with a spray electrical cleaner and rocking/operating the switch back and forth until it operates again. I used to do this without taking the console apart. I have had the same problem with the radio fader when it is located at the console as well, a gummed up radio fader can cause the whole radio to seemingly malfunction.

Who knows you might find some change :)

The console switches may be dirty but you've overlooked the window relays which do fail over time. These are usually with the fuses - 1 x 1 inch aluminum boxes about 1" high. They're interchangeable so one can find the failing one by a process of elimination.

(Thanks "Me" for the detail on getting at the switches))

Seems to me that if the relays failed then the window would not have gone down (it did go down but not up). That seems to suggest the switch, yes? Especially since the rear window goes up and down with the door switch but not the switch on the console. Thanks again, "me" for some good advise.

Peter

It's well known that Mercedes fuses can seem ok but not work

To rule this out, replace ALL the fuses, but only after you've throoughly cleaned the fusebox contacts. An ink erasor on the end o of a pen is good for doing this.

Keep in mind the windoe switched can be disassembled, cleaned and put back together. This aint a chevy and was meant to be fixed.

You'll invariably find black junk on copper inside. Just clean it up with an ink eraser.

If a new relay fixes it, then that's it. If you can find another one on the car that has he same relay type (ie, 87, 87a, etc) then swap and see.

It might be binding mechanically. If you can measure voltage at the motor then this is what's happening.

Thanks to everyone. After concluding it was the switch I called my favorite parts person in Seattle. This is not a commercial for Abe but I wish I could do everything to thank him. I spoke with Abe of Mercedes BMW Parts on Aurora. He knows EVERYTHING about MB parts. We discussed the wiring, motors, relays (there are none in this car) and switches. He had some OEM switches for about $100 for each side (left and right) or $45/50 for aftermarket. He said he hadn't heard of any problem with the aftermarket ones. He gave me the simple instructions for removing the switches. You don't have to remove anything on the console. Just use small screwdrivers to pry them up out of the facia. He said he'd send the switches out in the morning. He wouldn't take VISA but said to send him a check. He sent the switches out before even receiving the check! The switches arrived today and five minutes later I have 4 functioning windows.

I don't know if he has a website. I doubt it. It's a small operation. But if you need parts or just need advice, Abe is your guy. This is his Seattle number: 206-523-1804. Again, this isn't a commercial but the guy is a great resource and I thought you should know about him and the integrity he brings to his work.

Peter